通过微空气活性污泥工艺模拟工业废水中的氨留置过程中二氧化排放的评估
Xinyi Zhou1, Taku Fujiwara2, Taira Hidaka3
1Graduate School of Global Environmental Studies, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan.
Water research
|November 11, 2023
概括
本研究引入了用于高强度废水的微空气活性污泥 (MAS) 工艺,实现了80%以上的氨保留和90%的TOC去除. 然而,观察到大量的氧化 (N2O) 排放,突出显示了在氨回收过程中需要减轻排放的战略.
科学领域:
- 环境工程 环境工程
- 废水处理 废水处理
- 通过气循环的循环.
背景情况:
- 废水处理涉及复杂的转化,包括通过化和脱化固定和去除氨.
- 微空气活性污泥 (MAS) 工艺正在探索预处理,以保留氨- (NH4-N) 进行回收,同时抑制化.
- 了解温室气体排放,特别是氧化 (N2O),对于去除的过程至关重要.
研究的目的:
- 评估微空气活性污泥 (MAS) 工艺作为高强度废水的预处理,重点关注NH4-N的保留和总有机碳 (TOC) 的去除.
- 在受控的溶氧 (DO) 和pH条件下,在MAS过程中评估二氧化碳 (CO2) 和氧化 (N2O) 排放.
- 调查MAS系统中不同反应堆对N2O排放有助的机制和途径.
主要方法:
- 实施了三种具有受控DO和pH水平的基板规模MAS系统.
- 监测NH4-N和TOC清除效率的情况.
- 量化N2O和CO2排放量,并分析排放因子.
- 研究每个反应堆中N2O排放机制,考虑脱和生物氧化途径.
主要成果:
- 该MAS工艺实现了80%以上的NH4-N保留和90%以上的TOC去除.
- 总N2O排放量在407至475mg-N/day之间,排放因子超过总含量的2%.
- 显著的N2O排放源于第二反应堆 (69-80%),可能与NOx生产和生物NH2OH氧化有关.
- 在第三个反应堆中,化剂脱为N2O总排放量贡献了10-17%的贡献.
- 在pH 6.2与pH 6.8相比,观察到较低的N2O排放,这表明缓解的潜力.
结论:
- 该MAS过程有效地保留NH4-N和去除TOC,但与大量N2O排放有关.
- 在酸性条件下不完全化和大量的脱剂是导致高N2O排放的关键因素.
- 在稍微更酸的条件下运行 (pH 6.2) 显示了N2O缓解的潜力,需要进一步研究以优化氨回收过程.
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